A transparent conductive film is a film that is not only able to conduct electricity but also has a high transparency in the wavelength range of visible light. A common material of the transparent conductive film is tin-doped Indium oxide (ITO). The material can be widely used because it only absorbs ultraviolet light, but not absorb visible light due to its broad forbidden band width, and it has a good conductivity. The indium is present in lithosphere in a low quantity and in a wide dispersion form. Currently, no indium-rich ore is found, and indium is only present in zinc ores or other metal ores as impurity. Thus, indium is contemplated as a rare metal. With the progress in science and technology, the transparent conductive film will be widely used as electrode materials in electroluminescence devices, plant liquid crystal display devices and electrochromic display devices. However, indium, as a rare metal, has a limited total available quantity, and thus finding of a novel material of the transparent conductive film that can be used for replacing ITO would have important economic values.
Silver nanowires, in addition to excellent conductivity, ductility and tensile performance as possessed by conventional silver materials, have electrical and optical characteristics different from those of bulk silver materials due to unique dimension and morphological characteristics in nanometer size, and thus the silver nanowires can be used as the primary raw material in a novel transparent conductive film.
Materials for the transparent conductive film require a good conductivity, a high transparency and a low haze. The haze is used to show cloud-like or cloudy appearance of the interior or surface of a transparent or semi-transparent material as caused due to light diffusion, and the haze is relative to the roughness of the surface of the material. Silver nanowires as prepared by conventional methods have a diameter of about 60 nm, and a length between 2 and 100 Transparent conductive films as prepared with such silver nanowires can have a good conductivity and a high transparency, whereas the haze is very high, essentially being about 2.3%. Furthermore, the transparent conductive films highly require the haze, and in the display field, the haze of the transparent conductive films is required to be close to 1%. However, silver nanowires as prepared according to conventional methods can hardly satisfy the requirement.
Journal Paper A: one-step route to Ag nanowires with a diameter below 40 nm and an aspect ratio above 1000, DOI: 10.1039/C4cc04698f discloses a method for preparing silver nanowires, in which the prepared nanowires have a diameter of 30 nm or above. However, the inventor prepares a transparent conductive film with the silver nanowires on the basis of repeating the above experimental results to find out that the haze of the transparent conductive film is about 1.6%. As for applications of the silver nanowires in the display field, the haze is still overly high, and thus if using the material as prepared according to the method in the preparation of a transparent conductive film, the material hardly satisfies associated application standards.
In order to overcome the defect with regard to the high haze of current silver nanowires when being used for preparation of transparent conductive films, the intention provides a silver-chromium alloy nanowire and a method for preparation thereof. The silver-chromium alloy nanowires according to the invention have a lower diameter to be 18 nm. Thus, the silver-chromium alloy nanowires can be used as a raw material for preparing a transparent conductive film in replace of silver nanowires. Moreover, the nanowires can reduce the amount of silver and preparation costs and achieve a low haze.